The way the imported vehicle system works is "a potential safety risk," says the New Zealand Transportation Agency (NZTA).
The reason is the links between the companies that import and certify vehicles.
The agency said that someone with safety concerns about their vehicle should be checked by the certification authority.
It calls for the industry to submit by the end of the month, because it will start to hurt conflicts of interest in industry.
"Conflict of Interest" means a situation where a person who is required to perform inspections or certification activities of a vehicle is or could be affected or could reasonably be perceived as endangered by being threatened by the professional, financial or personal interest of the key entry and certification supply chain, "he said in an on-line statement
The main test company, VINZ, believes there is no perceived conflict of interest, despite being owned by the Japanese company Optimus, which also has import interests.
The NZTA suggests that entry inspectors can not control the vehicles that have been linked to them.
When the rules were created in 2014, "the integration of the supply chain of the used vehicles was expected and taken into account, but not to the extent that it subsequently occurred," he said.
"This means that one company could be responsible for some or all of the parts of the entry certification process."
The proposed new rules state that "recognizes that the process of vehicle entry certification plays a key role in promoting … public safety by ensuring that only safe second-hand vehicles are certified for use in New Zealand."
A whole new part of the rule would prohibit the import and control of all tied companies such as the same final holding company, joint directors or shareholders, or even any "close personal relationship".
RNZ identified three companies importing cars that also own compliance testing centers. However, the Agency stated that in each of these cases, actual on-the-spot checks were carried out by separate, approved control companies.